gas chromatography confusion

[lamborghiniMD]

Okay so elution time the same as retention time or is retention time the same as retention factor?

As which side of the graph shows the compound with the longest elution time (short Rf value) is the right side or left side of the graph?

I tried rereading this concept from TBR orgo but Im still confused. Thanks!

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[rjosh33]

Okay so elution time the same as retention time or is retention time the same as retention factor?

As which side of the graph shows the compound with the longest elution time (short Rf value) is the right side or left side of the graph?

I tried rereading this concept from TBR orgo but Im still confused. Thanks!

Retention time = elution time. It's the time that elapses from injection of mixture until the component of interest arrives at the detector.

Retention factor takes into account the time it takes the mobile phase (or unretained solute) to pass through the column as well, since that's the fastest it can possibly elute. Its formula is (Tr - Tm) / Tm, where Tr is retention time of the solute, and Tm is the time needed for mobile phase to arrive at the detector. Honestly, though, I doubt you'll have to know anything about retention factors.

For the graph, peaks from left to right go in order from shortest time to longest time. So those on the right will have been retained the longest.